Compression refrigerating machine with oil collecting space in the crankcase



W. HIRCHE Nov. 10, 1942.

COMPRESSION REFRIGERATING MACHINE WITH OIL COLLECTING SPACE IN THE CRANKCASE Filed Aug. 29, 1939 Patented Nov. 10, 1942 COMPRESSIONREFRIGERATING MACHINE WITH OIL COLLECTING SPACE IN THE CRANKCASE WillyHirche, Leopoldshain, Gorlitz-Land, Germany; vested in the AlienProperty Custodian Application August 29, 1939, Serial No. 292,383 InGermany September 1, 1938 4 Claims. (Cl. 62115) The invention relates toa compression refrigerating machine, in which the crank case isconstructed to provide an oil collector with the crank case shut off onall sides. In such machines it is unavoidable, that traces of oil escapefrom the crankcase between piston and cylinder wall and that, on theother hand, refrigerant vapours get from the stroke space of thecylinder into the crank case. Both these occurrences are detrimental tothe operation of the machine. Travelling oil particles reduce the oilquantity in the crank case and deposit it at other points of the plantthereby reducing its efiiciency. Refrigerant vapour which has leakedinto the crank case increases the pressure in the crank case, rendersdiflicult the running of the engine, finally condenses and impairs thelubricating capability of theoil.

According to the invention the foregoing inconveniences are obviated inthat arrangements are provided, which return to the proper place therefrigerant vapour which has penetrated into the crank case and thelubricant which has been removed from the crank case.

The drawing illustrates two embodiments of;

the invention.

Fig. 1 shows in vertical section one embodiment, and

Fig. 2 the second one.

The crank case designated by I merges at its top into the cylinder 2,-whereas the motor casing 3 is connected with one of its sides. The crankcase is air-tightly closed at all sides by the motor casing 3 and by thecylinder head 4. The crank shaft 5, carrying the rotor 5 of the drivingengine, is journalled at l and 8 in the crank case. The piston 9 isreciprocated in the cylinder 2 by the crank II and the connecting rodl0, The-shaft B carries at the end opposite the rotor a cylindricalslide valve l2 which tightly fits in the lateral extension [3. Therefrigerant vapour is conducted by the evaporator l4 through pipe intothe upper portion of a closed container IS, in which it strikes againsta partition [1, on which the oil particles separate which have beendrawn along, whereupon the refrigerant vapour flows through a pipe l8into the suction chamber IQ of the cylinder head 4, through the valveinto the stroke chamber of the cylinder, then through the valve 2| intothe pressure chamber 22 and finally into the condenser 23 from which thecondensed refrigerant, together with the oil particles drawn along, flowagain through a pipe l8 into the suction cham- 20 into the strokechamber of the cylinder, then through the valve 2| into the pressurechamber 22 and finally into the condenser 23, from which the condensedrefrigerant. together with the oil particles which have been drawn alongfiow again through an expansion device 24 back into the evaporator.

The lower portion of the crank case serves as oil collector. In thislower portion a pump 25 or any other distributor element is arranged, tolead the lubricant to the lubricating points. On the head of theconnecting rod a scoop may be arranged which dips into the collected oiland throws the oil about in the crank case. The oil also moistens therunning surface of the cylin- .der and is wiped ofi by the piston. Atthis occasion traces of oil get over the piston into the stroke chamberof the cylinder, are drawn along by. the refrigerant vapours and getinto the separator l6 together with the refrigerant through thecondenser and evaporator. In the separator the oil collects on thebottom and flows into a pipe 26 connected to the casing l3. Opposite themouth of the pipe 26 the rotary slide valve I2 has a pocket-likeindentation 21 in its circumference, which indentation fills with oil ifit is opposite the mouth of pipe 26. During the rotation of the slidevalve 12 the indentation or pocket 21 comes opposite a pipe 28 extendingfrom the crank case, so that the oil from the pocket 21 returns throughthe pipe 28 into the crank case.

The rotary slide valve does not admit of a direct communication of thecontainer IS with the crank case, as one of the pipes 26, 28 is alwaysshut ofi when the other communicates with the pocket 21, so that, forinstance when the machine is tilted during transport, the content of thecrank case cannot flow into other parts of the plant. On the other handthe oil is periodically returned from the container l6 .into the crankcase during the operation of the engine.

During the pressure stroke of the piston refrigerant vapours can getbetween piston and cylinder wall into the crank .case.- For returningthese vapours a pipe 29 extends from the upper portion of the crankcase, i. e; the steam chamber, and terminates in the casing I3 oppositean indentation or pocket 3!] in the rotary slide valve. A pipe 3|terminating in the suction pipe l5 branches from the casing l3 oppositethe line along which the indentation or pocket 30 rotates. If thepressure in the crank case has increased by vapours which havepenetrated into her IQ of the cylinder head 4, through the valve thecase, a periodic pressure equalization is efiectgem;

fected by pumps or other conveyingelements of suitable construction.

In the form of construction shown in Figl i the pressure equalisation iseffected in another manner. In this instance apocket 3.2 op n to der andcrank case closed on all sides with an oil collecting space in the crankcase, a gas and oil separator, conduits connecting the oil collectingspace and the separator, and means in said conduits for controlling thereturn of oil from the separator to the oil collecting space and thereturn of gas to the separator including a cylinder interposed in atleast one of said conduits, a plug rotatable in said cylinder and havinga surface indentation adapted during rotation of the plug ,toreceive-soil from the separator for return to @the'cranlg c aseandmeansin the other conduit to wards the cylinder wall is provided-in thelower" part of the piston wall, and arecess-tjtf-at. the

lower end of the cylinder in the side wall ofzthesame. A pipe 34extending from the container [6 terminates in the cylinder at theheight-"of idea may, however, be 'applied-alsoto refrigerating machineswith rotary compressor; Theinvention is not limited to the pos'itionpfthe compressor cylinder opp sitethecrank. casa'as this cylinder may bevertical, as shown the draw.- ing, but also hanging or horizontal. "I heidea is common to all forms of constructipn to return to heir prope plrei s a tramu which, has got into the crank case closed on allsidesandoil which hasescaped from lthe'crank case, and to prevent collection ofoil at any other point but in the crank casewhich forms the'only oilcol-' lecting space. The invention is particularly ad} vantageous forrefrigerating'plants with several evaporators.

I claim: a

1. A compression refrigeratingapparatus, comprising in combination witla compressor cylinder and crank case closed on all sides with an oilcollecting space in the crank case, a gas and oil separator, conduitsconnecting the oil collecting space and the separator; and means in Saidconduits for controlling the return of Oilfrom the separator to the oilcollecting space and theretum of gas to the separator including acylinder interposed in the conduits, a plug. rotatable in said cylinderandv having surface indentations adapted during rotation ,of the plugrespectively to receive gas and oil from the crankcaseand separator forreturn .of the gas to the separator and the return of the oil to thecrank case.

2. A compression refrigerating apparatus, cornprising in combinationwith a compressor cylin- "control the return of gas from the crank caseto the separator. I

v 3.11 compression refrigerating apparatus, comprising in combinationwith a compressor cylinder anda crank case closed on all sides with anoil collecting space in the crank case, a gas and oil separator,conduits connecting the oil collectingspace and the separator, and acontrolled element adapted to effect a pressure equalization between thecrank case and suction side of the machine and operative for controllingthe return of oil from the separator to the oil collecting space and thereturn of gas to the separator, including an extension projecting fromsaid crank case, a rotary slide valve. iri said extension and havingpocket like indentations in its circumference, an oil return pipeextending from-said extension in therotary plane of one of saidindentations and terminating in the crank case, and a-pressurecompensatingpipe extending from the other of said pocket-likeindentations in the rotary'plane of the other pf said indentationsandterminating thecrank case.

4. A compression refrigerating apparatus, comprising combination with acompressor cylinder and a crankcase closed on all 'sides with an oilcollecting space inthe crank case, a. gas and oil para or u t n n liht lnwing "spec and ,the' separator, and a controlled element adaptedtoefie'ct apressuree'qualization between the cram case and suction sideof the machine and'operative for controlling the return of oil from theseparator to the oil collecting space and the return of gas to theseparator, including an extension of said crank case, a rotary slidevalve'in said extension and having a pocketlike indentation in itscircumference, an oil. return pipe extending from said extension in therotary plane of said indentation and terminating in said crank case, apiston in said cylinder having a pocket-like indentation open towardsthe crank case wall, a connecting pipe extending from said separator tosaid crank case wall to said 'pocket 'like findentation" in the piston,a pocket in said crankcase under said piston and open towards'the innerand lower sides through whichwhen'the piston is infthe lowermost'position refrigerant gas can flow into said indentation, aconnectingpipe between the cylinder and the oil separator adapted to conduct gasof the refrigerating medium from said pocket into said separator.

. WILLY HIRCi-IE.

